Latest: Ryanair boss Michael O’Leary says airline in a “mess”

Update 2.20pm: Ryanair’s chief executive has admitted the airline is in “a mess” over its plans to cancel thousands of flights over the next six weeks.

“We sincerely apologise and we are working very hard at the moment to make sure we finalise the list of flight cancellations which will effect less than 2% of our customers and we will look after those customers who have been distrupted,” he said.

Earlier:Ireland’s aviation regulator has said Ryanair must offer alternative flights or a full refund if it cancels a service.

The budget airline is under pressure to publish a full list of the flights it plans to cancel over the next six weeks as customers have become increasingly angry.

It said it was shelving up to 50 flights daily after it “messed up” the planning of pilot holidays.

Ireland’s Commission for Aviation Regulation said: “If Ryanair cancels a flight, it must offer you the choice of an alternative flight at the earliest opportunity or at a later date of your choice subject to the availability of seats or a full refund of the ticket.”

The commission, which has responsibility for scheduling at Irish airports, is due to meet to discuss the situation.

It has said it expects Ryanair to pay out compensation in some cases.

Over the weekend the airline published a list of affected flights up to Wednesday.

Which? consumers’ group said: “It’s also essential that Ryanair release a full list of flights that will be affected so that passengers have as much time as possible to make alternate arrangements.”

It was reported that recruitment problems were affecting the airline and it had lost a significant number of pilots to low cost rival Norwegian Air, something denied by Ryanair.

Kenny Jacobs, chief marketing officer at Ryanair, said the company was “working hard to fix” the problem, after it announced a 2% reduction in scheduled flights until the end of October as it shifts to conform with European regulations surrounding staff leave.

Changes imposed by Irish regulators, in line with European law, forces Ryanair to conform staff holidays with the calendar year from January, requiring it to allocate that leave before the end of the year.

Ryanair said air traffic control delays and strikes, bad weather and a backlog of annual leave to be taken by pilots and cabin crew had led to punctuality falling to below 80% over the last two weeks.

A spokesman said this figure was “unacceptable” and the company has apologised to affected customers, who it said will be offered alternative flights or refunds.

Some customers said last-minute cancellations had left them out-of-pocket due to non-refundable accommodation costs, or with no choice but to book expensive alternative flights or transport.

Others said they had been left stranded in their holiday destination and many urged Ryanair to publish a list of all flight cancellations.

The vast majority of UK cancellations affected Stansted. Some Dublin flights were also dropped.